diff mbox series

[v2,3/5] blk-iocost: Move the usage ratio calculation to the correct place

Message ID a4e6af93419250de5372ff681d3395cf36676037.1606378475.git.baolin.wang@linux.alibaba.com (mailing list archive)
State New, archived
Headers show
Series Some cleanups and improvements for blk-iocost | expand

Commit Message

Baolin Wang Nov. 26, 2020, 8:16 a.m. UTC 
We only use the hweight based usage ratio to calculate the new
hweight_inuse of the iocg to decide if this iocg can donate some
surplus vtime.

Thus move the usage ratio calculation to the correct place to
avoid unnecessary calculation for some vtime shortage iocgs.

Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
---
 block/blk-iocost.c | 44 +++++++++++++++++++++++---------------------
 1 file changed, 23 insertions(+), 21 deletions(-)

Comments

Tejun Heo Dec. 2, 2020, 7:56 p.m. UTC | #1 
On Thu, Nov 26, 2020 at 04:16:13PM +0800, Baolin Wang wrote:
> We only use the hweight based usage ratio to calculate the new
> hweight_inuse of the iocg to decide if this iocg can donate some
> surplus vtime.
> 
> Thus move the usage ratio calculation to the correct place to
> avoid unnecessary calculation for some vtime shortage iocgs.
> 
> Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>

Acked-by: Tejun Heo <tj@kernel.org>

Thanks.
diff mbox series

Patch

diff --git a/block/blk-iocost.c b/block/blk-iocost.c
index 103ccbd..a926179 100644
--- a/block/blk-iocost.c
+++ b/block/blk-iocost.c
@@ -2168,8 +2168,8 @@  static void ioc_timer_fn(struct timer_list *timer)
 
 	/* calc usage and see whether some weights need to be moved around */
 	list_for_each_entry(iocg, &ioc->active_iocgs, active_list) {
-		u64 vdone, vtime, usage_us, usage_dur;
-		u32 usage, hw_active, hw_inuse;
+		u64 vdone, vtime, usage_us;
+		u32 hw_active, hw_inuse;
 
 		/*
 		 * Collect unused and wind vtime closer to vnow to prevent
@@ -2200,30 +2200,32 @@  static void ioc_timer_fn(struct timer_list *timer)
 		usage_us = iocg->usage_delta_us;
 		usage_us_sum += usage_us;
 
-		if (vdone != vtime) {
-			u64 inflight_us = DIV64_U64_ROUND_UP(
-				cost_to_abs_cost(vtime - vdone, hw_inuse),
-				ioc->vtime_base_rate);
-			usage_us = max(usage_us, inflight_us);
-		}
-
-		/* convert to hweight based usage ratio */
-		if (time_after64(iocg->activated_at, ioc->period_at))
-			usage_dur = max_t(u64, now.now - iocg->activated_at, 1);
-		else
-			usage_dur = max_t(u64, now.now - ioc->period_at, 1);
-
-		usage = clamp_t(u32,
-				DIV64_U64_ROUND_UP(usage_us * WEIGHT_ONE,
-						   usage_dur),
-				1, WEIGHT_ONE);
-
 		/* see whether there's surplus vtime */
 		WARN_ON_ONCE(!list_empty(&iocg->surplus_list));
 		if (hw_inuse < hw_active ||
 		    (!waitqueue_active(&iocg->waitq) &&
 		     time_before64(vtime, now.vnow - ioc->margins.low))) {
-			u32 hwa, old_hwi, hwm, new_hwi;
+			u32 hwa, old_hwi, hwm, new_hwi, usage;
+			u64 usage_dur;
+
+			if (vdone != vtime) {
+				u64 inflight_us = DIV64_U64_ROUND_UP(
+					cost_to_abs_cost(vtime - vdone, hw_inuse),
+					ioc->vtime_base_rate);
+
+				usage_us = max(usage_us, inflight_us);
+			}
+
+			/* convert to hweight based usage ratio */
+			if (time_after64(iocg->activated_at, ioc->period_at))
+				usage_dur = max_t(u64, now.now - iocg->activated_at, 1);
+			else
+				usage_dur = max_t(u64, now.now - ioc->period_at, 1);
+
+			usage = clamp_t(u32,
+				DIV64_U64_ROUND_UP(usage_us * WEIGHT_ONE,
+						   usage_dur),
+				1, WEIGHT_ONE);
 
 			/*
 			 * Already donating or accumulated enough to start.